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Wave dynamics over Roberts Bank, British Columbia: processes and modelling

TL;DR: Meule et al. as discussed by the authors used a wave and current measurement station on the upper delta slope of Roberts Bank in approximately 12 m of water to determine wave characteristics for fair-weather, moderate, and storm conditions.
Abstract: Between 1 March and 26 March 2002, a wave and current measurement station was deployed on the upper delta slope of Roberts Bank in approximately 12 m of water. The field data were analyzed and used in a parabolic wave model to determine wave characteristics for fair-weather, moderate, and storm conditions. The model shows that storm waves act nonuniformly along the beach depending on the local morphology and tidal elevation. Waves propagating during high tide are characterized by smooth dissipation and progressive refraction, whereas waves propagating during low tide show intense refraction and breaking in front of or over a low-tide bar. Sediment transport divergence in the nearshore is strongly controlled by the temporal relationship between storm waves and tidal height. Resume : Entre le 1er et le 26 mars 2002, une station instrumentee a ete deployee sur la partie superieure de la pente deltaique du banc Roberts, dans approximativement 12 m d’eau, afin de mesurer la houle et les courants. Les donnees de terrain ont ete ensuite analysees et utilisees dans un modele parabolique de houle afin de determiner les caracteristiques des houles pendant les conditions de beau temps, moderees et de tempete. Le modele montre que les houles de tempete agissent non uniformement le long de la plage selon la morphologie locale et le marnage. La propagation de la houle a maree haute est caracterisee par une legere dissipation et une refraction progressive tandis que les houles se propageant a maree basse montrent une intense refraction et deferlent sur le front ou au-dessus d’une barre de maree basse. La divergence du transport sedimentaire dans la zone littorale est fortement controlee par la relation temporelle entre les houles de tempete et le niveau de la maree. Current Research 2007-A11 1 S. Meule et al.
Citations
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01 Jul 1978
TL;DR: In this paper, a parabolic approximation to the reduced wave equation was proposed for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components, and the asymptotic form of the solution was compared with the geometrical optics approximation.
Abstract: A parabolic approximation to the reduced wave equation is investigated for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components. In the case of an area with straight and parallel bottom contourlines, the asymptotic form of the solution fer high frequencies is compared with the geometrical optics approximation. Two numerical solution techniques are applied to the propagation of an incident plane wave ever a circular shoal.

22 citations

Journal ArticleDOI
TL;DR: In this paper, a 1.6-yr time series of radial current velocity from a 25MHz high-frequency radar system located near a coastal river plume is analyzed to determine how the working range varies in response to changing near-surface conductivity, sea state, and tides.
Abstract: A 1.6-yr time series of radial current velocity from a 25-MHz high-frequency radar system located near a coastal river plume is analyzed to determine how the working range varies in response to changing near-surface conductivity, sea state, and tides. Working range is defined as the distance to the farthest radial velocity solution along a fixed bearing. A comparison to spatially resolved near-surface conductivity measurements from an instrumented ferry shows that fluctuations in conductivity had the largest impact of the three factors considered. The working range increases nearly linearly with increasing conductivity, almost doubling from 19.4 km at 0.9 S m−1 to 37.4 km at 3.5 S m−1, which yields a slope of 7.0 km per S m−1. The next largest factor was sea state, which was investigated using measured winds. The working range increases linearly at a rate of 1 km per m s−1 of wind speed over the range of 0.5–6.5 m s−1, but it decreases weakly for wind speeds higher than 7.5 m s−1. Finally, a power...

8 citations


Cites background or result from "Wave dynamics over Roberts Bank, Br..."

  • ...Although significant wave heights reach as high as 2.5m, 97% of all hourly values are below 1m—consistent with previous observations made nearer to the radar footprint (Meulé et al. 2007)....

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  • ...The wave conditions experienced in this region depend somewhat on the wind direction because it determines the fetch (Meulé et al. 2007)....

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References
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Book
21 Jul 1992
TL;DR: In this article, a review of bottom boundary layer flows including the boundary layer interaction between waves and steady currents is presented, and the concept of eddy viscosity for these flows is discussed in depth because of its relation to sediment diffusivity.
Abstract: This book is intended as a useful handbook for professionals and researchers in the areas of Physical Oceanography, Marine Geology, Coastal Geomorphology and Coastal Engineering and as a text for graduate students in these fields. With its emphasis on boundary layer flow and basic sediment transport modelling, it is meant to help fill the gap between general hydrodynamic texts and descriptive texts on marine and coastal sedimentary processes. The book commences with a review of coastal bottom boundary layer flows including the boundary layer interaction between waves and steady currents. The concept of eddy viscosity for these flows is discussed in depth because of its relation to sediment diffusivity. The quasi-steady processes of sediment transport over flat beds are discussed. Small scale coastal bedforms and the corresponding hydraulic roughness are described. The motion of suspended sand particles is studied in detail with emphasis on the possible suspension maintaining mechanisms in coastal flows. Sediment pickup functions are provided for unsteady flows. A new combined convection-diffusion model is provided for suspended sediment distributions. Different methods of sediment transport model building are presented together with some classical models.

1,311 citations

Journal ArticleDOI
29 Jan 1972
TL;DR: In this paper, the derivation of a two-dimensional differential equation, which describes the phenomenon of combined refraction - diffraction for simple harmonic waves, and a method of solving this equation is presented.
Abstract: This paper treats the derivation of a two-dimensional differential equation, which describes the phenomenon of combined refraction - diffraction for simple harmonic waves, and a method of solving this equation The equation is derived with the aid of a small parameter development, and the method of solution is based on the finite element technique, together with a source distribution method

756 citations


"Wave dynamics over Roberts Bank, Br..." refers methods in this paper

  • ...The elliptic equation of Berkhoff (1972, 1976) was not used in its original form....

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Journal ArticleDOI
TL;DR: In this paper, a parabolic approximation to the reduced wave equation was proposed for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components.
Abstract: A parabolic approximation to the reduced wave equation is investigated for the propagation of periodic surface waves in shoaling water. The approximation is derived from splitting the wave field into transmitted and reflected components.In the case of an area with straight and parallel bottom contour lines, the asymptotic form of the solution for high frequencies is compared with the geometrical optics approximation.Two numerical solution techniques are applied to the propagation of an incident plane wave over a circular shoal.

348 citations


Additional excerpts

  • ...For computational efficiency, the main direction of wave propagation was projected onto the X-axis and equation 2 was solved in a parabolic form (Radder, 1979): ∂ ∂ ∂ ∂ φ φ x ik kCCg kCCg x = ⎞ ⎠ ⎟ ⎛ ⎝ ⎜ + 1 2 (3) i kCCg y CCg y2 ∂ ∂ ∂ ∂ φ⎞ ⎠ ⎟ ⎛ ⎝ ⎜ where i is the imaginary number....

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Journal ArticleDOI
TL;DR: In this paper, the authors show that the flow field of waves breaking on a gently sloping beach is similar to that of hydraulic jumps and support the use of the hydraulic jump formulation for the breaking wave energy dissipation.

109 citations


Additional excerpts

  • ...When waves break, the surface elevation in the surf zone is recalculated from the equation of Stive (1984): ∂ ∂ ∂ ∂ H x H h h x A h gT H h + = ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ ⎞ ⎠⎟ ⎛ ⎝ ⎜⎜∈4 2 1 2 2 (4) where H is the wave height, h is the depth, A is a dimensionless dissipation factor, g is the acceleration due to…...

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